This article is from a symposium, Five Approaches to Legal Reasoning in the Classroom: Contrasting Perspectives on O\u27Brien v. Cunard S.S. Co. Ltd., 57 Missouri L. Rev. 345 (1992). The symposium contains five articles that analyze this case from, respectively, traditionalist, Law & Economics, Critical Legal Studies, Feminist, and Critical Race Theories perspectives. This article analyzes the O\u27Brien case from a Law & Economics perspective. It does so in a manner suitable for presentation in a Torts class or a Law & Economics class. It explains the basic terminology and approach. It analyzes the economics underlying the vaccination requirement, whether Cunard should be liable for its physician\u27s negligence, and the informed consent...